This drum brake has an advanced leading/trailing design. A
single universal spring performs 2 functions. The drum has the following advantages:
| • | Equivalent in performance to other drum brakes |
| • | Holds both the shoe and the lining assemblies to the backing plate. |
| • | Acts as a retractor spring for the assemblies. |
When the brakes are applied, the wheel cylinder moves both shoes out
in order to contact the drum. With forward wheel rotation, the forward (leading)
brake shoe wraps into the drum and self-energizes. Force from the shoes
is transferred through the fixed anchor and backing plate to the axle flange.
The drum brakes self-adjust during any brake application, with no vehicle
motion required. Once the shoes are installed, do not switch the positions,
even though the forward shoe normally wears faster than the rear shoe. Switching
positions may render the self-adjustment inoperative and result in increased
pedal travel. For diagnosis of this system, refer to
Hydraulic Brake Diagnostic System Check
in Hydraulic
Brakes.
